/* roulang page: index */
:root {
      --neon: #00E5FF;
      --neon-hover: #00BCD4;
      --deep-bg: #0A1628;
      --text-dark: #1F2937;
      --text-muted: #6B7280;
      --text-soft: #4B5563;
      --bg-light: #F4F7FA;
      --card-bg: #FFFFFF;
      --border-light: #E5E7EB;
      --shadow-sm: 0 4px 20px rgba(0, 0, 0, 0.04);
      --shadow-hover: 0 12px 32px rgba(0, 0, 0, 0.08);
      --radius-lg: 16px;
      --radius-md: 8px;
      --transition: 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: #FFFFFF;
      color: var(--text-dark);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }

    /* 导航栏 */
    .navbar {
      background-color: var(--deep-bg);
      position: sticky;
      top: 0;
      z-index: 50;
      height: 72px;
      border-bottom: 2px solid transparent;
      transition: border-color 0.2s;
    }
    .navbar.active-border {
      border-bottom-color: var(--neon);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .brand {
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .brand-logo {
      font-weight: 700;
      font-size: 1.5rem;
      color: #FFFFFF;
      letter-spacing: 0.5px;
    }
    .brand-domain {
      font-size: 0.75rem;
      color: rgba(255,255,255,0.5);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
    }
    .nav-links a {
      color: rgba(255,255,255,0.85);
      font-size: 0.95rem;
      font-weight: 500;
      padding: 8px 0;
      position: relative;
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: #FFFFFF;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background-color: var(--neon);
      transition: width 0.25s ease;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .nav-links a.active {
      color: #FFFFFF;
      text-shadow: 0 0 8px rgba(0,229,255,0.6);
    }
    .btn-neon {
      background-color: var(--neon);
      color: #0A1628;
      font-weight: 600;
      padding: 10px 22px;
      border-radius: var(--radius-md);
      border: none;
      cursor: pointer;
      transition: background 0.25s, box-shadow 0.25s;
      font-size: 0.95rem;
    }
    .btn-neon:hover {
      background-color: var(--neon-hover);
      box-shadow: 0 0 16px rgba(0,229,255,0.5);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: white;
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      height: calc(100vh - 72px);
      background: var(--deep-bg);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      z-index: 40;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s;
    }
    .mobile-menu.open {
      display: flex;
      opacity: 1;
      pointer-events: auto;
    }
    .mobile-menu a {
      color: rgba(255,255,255,0.9);
      font-size: 1.5rem;
      font-weight: 500;
    }

    @media (max-width: 1024px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
    }

    /* Hero */
    .hero {
      min-height: 90vh;
      background: linear-gradient(0deg, rgba(10,22,40,0.7) 0%, rgba(10,22,40,0.4) 100%), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      display: flex;
      align-items: center;
      color: white;
    }
    .hero-content {
      max-width: 800px;
    }
    .hero h1 {
      font-size: 3.5rem;
      font-weight: 700;
      letter-spacing: -0.5px;
      margin-bottom: 1.5rem;
      line-height: 1.2;
    }
    .hero p {
      font-size: 1.25rem;
      opacity: 0.9;
      margin-bottom: 2.5rem;
    }
    .btn-outline-neon {
      background: transparent;
      border: 2px solid var(--neon);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-md);
      transition: 0.25s;
    }
    .btn-outline-neon:hover {
      background: var(--neon);
      color: #0A1628;
    }
    @media (max-width: 768px) {
      .hero h1 { font-size: 2.2rem; }
      .hero p { font-size: 1rem; }
    }

    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section { padding: 60px 0; }
    }
    .section-title {
      font-size: 2.5rem;
      font-weight: 700;
      color: #0A1628;
      text-align: center;
      margin-bottom: 48px;
    }

    .card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      transition: transform 0.3s, box-shadow 0.3s;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }

    .bg-light-section {
      background-color: var(--bg-light);
    }

    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: #4B5563;
      line-height: 1.8;
      margin-top: 0;
    }
    .faq-answer.open {
      max-height: 200px;
      margin-top: 12px;
    }

    .footer {
      background: var(--deep-bg);
      color: rgba(255,255,255,0.8);
      padding: 60px 0 30px;
    }
    .footer a {
      color: rgba(255,255,255,0.7);
    }
    .footer a:hover {
      color: var(--neon);
    }